End Function

This returns a good result.
{"access_token":"0bb5654b8cd74aaeaf2242565d05317e","token_type":"bearer","ref":{"type":"app","id":999},"expires_in":28800,"refresh_token":"385466e5726c42599cad600d9d1307f0"}

End Function

But here I always get en error as result:
{"error_parameters":{},"error_detail":null,"error_propagate":false,"request":{"url":"http:\/\/api.podio.com\/item\/app\/999","query_string":"Authorization:OAuth2%200bb5654b8cd74aaeaf2242565d05317e\"","method":"GET"},"error_description":"invalid_request","error":"unauthorized"}

I think I did all as in your dokumentation. Have you any idea what is wrong with the get function?